Occlusal stability

As discussed in Chapter 1, any new restoration must be in harmony

with the existing occlusion if this is satisfactory, but may be used to

create a new occlusal relationship in situations when the existing

pattern is not satisfactory. In order for this to be determined, preoperative

examination of the occlusion is obviously essential. This may

involve the use of study models mounted with a face bow record on

an articulator, especially if multiple units or units involving guiding

surfaces are to be restored. Note must be taken of existing relationships,

both static (intercuspal position) and excursive (canine

guidance or group function, anterior guidance and the presence of

excursive interferences or gross discrepancies in movement from a

retruded position to the intercuspal position).

The new restoration should be constructed such that it has

sufficient contacts with the opposing tooth/teeth to maintain a stable

relationship, which will also depend upon the durability of the

material from which it is constructed. In addition, if the restoration

is to provide a guiding surface, then the nature of this guidance (for

example, whether to copy or change the existing relationship) must be

carefully planned before the preparation is commenced.